Dysphagia in a patient with lateral medullary syndrome: insight into the central control of swallowing

Relationship between Swallowing Pressure and Saliva Residue on Endoscopic Evaluation in Pharyngeal Dysphagia

OBJECTIVE

In pharyngeal dysphagia, poor pharyngeal contraction and upper esophageal sphincter (UES) dysfunction result in post-swallow saliva residue (SR). This study aimed to clarify the relationship between swallowing pressure and SR in the valleculae and piriform sinuses on flexible endoscopic evaluation of swallowing (FEES).

METHODS

Pharyngeal dysphagia patients with Wallenberg syndrome were included. Amounts of post-swallow SR in the valleculae and piriform sinuses were classified into four grades using SR scores based on FEES. The Hyodo score was also calculated to evaluate swallowing function. High-resolution manometric data in the nasopharyngeal, oropharyngeal, hypopharyngeal, oro-hypopharyngeal, and UES zones on swallowing were obtained for comparison with SR and Hyodo scores.

RESULTS

Of the 31 recruited, data from 26 patients who successfully underwent FEES and manometry were analyzed. Vallecular SR scores were strongly negatively correlated with a maximum pressure of the oropharynx (r = -0.52, p = 0.006), distal contractile integrals (DCI) of the oropharynx (r = -0.52, p = 0.007), and DCI of the oro-hypopharynx (r = -0.55, p = 0.004). Hyodo scores for parameters 1 and 4 (corresponding to salivary pooling and pharyngeal clearance, respectively) were strongly negatively correlated with a maximum hypopharyngeal pressure (r = -0.57, p = 0.002) and strongly positively correlated with peristaltic velocity (r = 0.53, p = 0.007), respectively. SR scores and Hyodo scores related to SR were not correlated with pressure data of the UES.

CONCLUSION

Manometric analysis of our SR scoring method using FEES revealed that a higher amount of SR in the valleculae, but not in the piriform sinuses, is associated with weaker pharyngeal pressure in pharyngeal dysphagia, especially at the oropharyngeal level.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3519-3526, 2024.

Development and validation of a novel nomogram model to assess the risk of gastric contents in outpatients undergoing elective sedative gastrointestinal endoscopy procedures

BACKGROUND

Gastric contents may contribute to patients' aspiration during anesthesia. Ultrasound can accurately assess the risk of gastric contents in patients undergoing sedative gastrointestinal endoscopy (GIE) procedures, but its efficiency is limited. Therefore, developing an accurate and efficient model to predict gastric contents in outpatients undergoing elective sedative GIE procedures is greatly desirable.

METHODS

This study retrospectively analyzed 1501 patients undergoing sedative GIE procedures. Gastric contents were observed under direct gastroscopic vision and suctioned through the endoscope. High-risk gastric contents were defined as having solid content or liquid volume > 25 ml and pH < 2.5; otherwise, they were considered low-risk gastric contents. Univariate analysis and multivariate analysis were used to select the independent risk factors to predict high-risk gastric contents. Based on the selected independent risk factors, we assigned values to each independent risk factor and established a novel nomogram. The performance of the nomogram was verified in the testing cohort by the metrics of discrimination, calibration, and clinical usefulness. In addition, an online accessible web calculator was constructed.

RESULTS

We found BMI, cerebral infarction, cirrhosis, male, age, diabetes, and gastroesophageal reflux disease were risk factors for gastric contents. The AUROCs were 0.911 and 0.864 in the development and testing cohort, respectively. Moreover, the nomogram showed good calibration ability. Decision curve analysis and Clinical impact curve demonstrated that the predictive nomogram was clinically useful. The website of the nomogram was https://medication.shinyapps.io/dynnomapp/.

CONCLUSIONS

This study demonstrates that clinical variables can be combined with algorithmic techniques to predict gastric contents in outpatients. Nomogram was constructed from routine variables, and the web calculator had excellent clinical applicability to assess the risk of gastric contents accurately and efficiently in outpatients, assist anesthesiologists in assessment and identify the most appropriate patients for ultrasound.

Quantitative Analysis of Temporal Parameters Correlated with Aspiration and Lesion Location in Stroke Patients

The purpose of this study was to identify differences in temporal parameters correlating to the presence of aspiration and the severity of penetration-aspiration scale (PAS) in patients with dysphagia after stroke. We also investigated whether there was a significant difference in temporal parameters based on the location of the stroke lesion. A total of 91 patient videofluoroscopic swallowing study (VFSS) videos of stroke patients with dysphagia were retrospectively analyzed. Various temporal parameters including oral phase duration, pharyngeal delay time, pharyngeal response time, pharyngeal transit time, laryngeal vestibule closure reaction time, laryngeal vestibule closure duration, upper esophageal sphincter opening duration and upper esophageal sphincter reaction time were measured. Subjects were grouped by the presence of aspiration, PAS score, and location of the stroke lesion. Pharyngeal response time, laryngeal vestibule closure duration, and upper esophageal sphincter opening duration were significantly prolonged in the aspiration group. These three factors showed positive correlation with PAS. In terms of stroke lesion, oral phase duration was significantly prolonged in the supratentorial lesion group, while upper esophageal sphincter opening duration was significantly prolonged in the infratentorial lesion group. We have demonstrated that quantitative temporal analysis of VFSS can be a clinically valuable tool identifying dysphagia pattern associated with stroke lesion or aspiration risk.

Research on Relationship Between Dysphagia and Sudden Death After Medullary Infarction

BACKGROUND

Medullary infarction (MI) often leads to severe dysphagia and sudden death. We investigated whether dysphagia was associated with sudden death.

METHODS

Patients with MI were divided into sudden death group and nonsudden death group. Dysphagia was evaluated in 2 ways: the water-swallowing test (WST) points and the degree of dysphagia. Random undersampling (RUS), random oversampling (ROS), and synthetic minority oversampling technique (SMOTE) techniques were used to process the original data and solve the imbalance problem between 2 classes. Univariate and multivariate logistic regressions were used to analyze the association between the independent variables (WST and degree of dysphagia) and the dependent variable (sudden death or not), while the National Institutes of Health Stroke Scale (NIHSS) score was used as a control.

RESULTS

Univariate logistic regression analysis showed that for all resampling methods, both the WST and NIHSS were risk factors for sudden death after MI. For multivariable logistic regression, the fitting effect of RUS logistic regression was satisfactory, which showed the same results. The results of the univariate logistic regression analysis of dysphagia degree showed that for all resampling methods, compared with no dysphagia, both mild to moderate dysphagia degree and severe dysphagia degree were risk factors for sudden death. For multivariable logistic regressions, the logistic regressions of the original data and the RUS resampling method were satisfactory which showed the same results.

CONCLUSIONS

Dysphagia is closely related to sudden death after MI. The more severe the dysphagia, the higher is the incidence of sudden death.

Dysphagia in lateral medullary syndrome

Introduction. The lateral medullary syndrome is a neurological disease caused by ischemia in the lateral part of the medulla oblongata and is the most common form of brainstem infarction. Dysphagia is a common and clinically significant symptom of this disease because it is closely associated with the risk of recurrent pneumonia, malnutrition, dehydration, and an increase in mortality and prolonged hospital treatment. Aim. This paper aims to review and analyze data on the correlation between swallowing disorders and lateral medullary syndrome. We intend to present the symptoms, diagnostic and therapeutic procedures of dysphagia in patients with this syndrome in a comprehensive way. Methodology. The following databases were used to search the literature: KoBSON-Consortium of Serbian Libraries for Unified Procurement, PubMed, Science Direct. Results. Based on the results of the reviewed studies, it was determined that patients with the lateral medullary syndrome often have swallowing disorders. They are often fed through a nasogastric tube a few months after the stroke, which significantly impairs their quality of life. To overcome swallowing disorders and create conditions for safe swallowing function, most patients need treatment for a longer period. In addition to the available screening tests, instrumental diagnostic methods provide insight into the biomechanical aspects of swallowing disorders, determine the risk of aspiration, and provide a starting point for selecting treatment strategies. Conclusion. Treatment of dysphagia depends on the mechanisms of occurrence and the predictors of recovery of swallowing function. When conducting treatment, among other things, it is very important to know the pathological mechanisms of neural connections of the medulla oblongata.

Postoperative Dysphagia Aortica: Comparison with Other Dysphagia

Dysphagia can be classified as oropharyngeal or esophageal, and functional or structural deficits of the esophagus can cause esophageal dysphagia. Dysphagia aortica (DA) is defined as dysphagia caused by extrinsic compression of the esophagus by the aorta. The aim of this study was to investigate the characteristics of DA by comparing the findings of videofluoroscopic swallowing studies (VFSS) with those of other dysphagia. Sixty-seven patients with postoperative dysphagia aortica (PDA), dysphagia after brainstem infarction (DBI), dysphagia after anterior cervical discectomy and fusion (DACDF), and subjective swallowing difficulty (SSD) without penetration and/or aspiration, who had undergone VFSS incorporating tests using 5 ml of thin and thick liquids, were included. The clinical data were collected retrospectively. The penetration-aspiration scale, functional dysphagia scale (FDS), esophageal transit time (ETT), and aortic lesion parameters (maximal diameter and distance between the lesion and the apex of the aortic arch) were assessed. The patients with PDA had higher FDS scores than the patients with SSD and lower scores than the patients with DBI did on thin liquids, while the FDS scores on thick liquids were lower in the patients with PDA than in those with DBI or DACDF. The patients with PDA had longer ETT than the other three groups. No correlation was found between the aortic lesion parameters and the VFSS findings. Although PDA has some oropharyngeal symptoms, the esophageal phase was affected mainly by PDA. After an operation on the aorta, VFSS should be considered before resuming oral feeding.

Neural correlates of cricopharyngeal dysfunction after supratentorial stroke: A voxel-based lesion-symptom mapping with propensity score matched case-control

BACKGROUND

Poststroke cricopharyngeal dysfunction has been reported to occur in 50% of brainstem strokes; however, cricopharyngeal dysfunction also occurs commonly in patients with supratentorial stroke. The hemispheric neuroanatomical location of this dysfunction has not been clearly identified.

AIM

We aimed to analyze the relationship between cricopharyngeal dysfunction and supratentorial lesion location in poststroke patients through this retrospective case-control voxel-based lesion-symptom mapping study.

METHODS

Cricopharyngeal dysfunction was diagnosed when the residue after swallowing (pyriform sinus) accounted for more than 25% of volume of pyriform sinus. Medical records and the video fluoroscopic swallowing studies of first-ever stroke patients who were admitted to our hospital during acute to subacute phase from 2009 to 2019 were reviewed. After propensity score matching to reduce the likelihood of selection bias, 50 patients per group were included in the cricopharyngeal dysfunction and control groups. We used a P threshold of 0.01 corrected for multiple comparisons with permutation thresholding (5000 permutations). Dichotomized diagnosis of cricopharyngeal dysfunction and the magnitude of pyriform sinus were used as dependent variables.

RESULTS

Analysis using the Liebermeister statistics indicated that lesions of the right lentiform nucleus were associated with the development of cricopharyngeal dysfunction. After adjustment for age and total lesion volume, which are known effectors for the development of dysphagia, statistically significant correlations were found between pyriform sinus and lesions of the right lentiform nucleus and anterior corona radiata beneath the right middle frontal gyrus.

CONCLUSION

Thus, our study demonstrated for the first time that damages to the right lentiform nucleus, especially globus pallidus externa, and anterior corona radiata beneath the right middle frontal gyrus are associated with the development and severity of cricopharyngeal dysfunction.

Pre- and Post-Surgical Dysphagia in Adults with Tumors of the Posterior Fossa: A Prospective Blinded Study

BACKGROUND

While swallowing disorders are frequent sequela following posterior fossa tumor (PFT) surgery in children, data on dysphagia frequency, severity, and outcome in adults are lacking. The aim of this study was to investigate dysphagia before and after surgical removal of PFT. Additionally, we tried to identify clinical predictors for postsurgical swallowing disorders. Furthermore, this study explored the three-month outcome of dysphagic patients.

METHODS

In a cohort of patients undergoing PFT surgery, dysphagia was prospectively assessed pre- and postoperatively using fiberoptic endoscopic evaluation of swallowing. Patients with severe dysphagia at discharge were re-evaluated after three months. Additionally, clinical and imaging data were collected to identify predictors for post-surgical dysphagia.

RESULTS

We included 26 patients of whom 15 had pre-operative swallowing disorders. After surgery, worsening of pre-existing dysphagia could be noticed in 7 patients whereas improvement was observed in 2 and full recovery in 3 subjects. New-onset dysphagia after surgery occurred in a minority of 3 cases. Postoperatively, 47% of dysphagic patients required nasogastric tube feeding. Re-evaluation after three months of follow-up revealed that all dysphagic patients had returned to full oral intake.

CONCLUSION

Dysphagia is a frequent finding in patients with PFT already before surgery. Surgical intervention can infer a deterioration of impaired swallowing function placing affected patients at temporary risk for aspiration. In contrast, surgery can also accomplish beneficial results resulting in both improvement and full recovery. Overall, our findings show the need of early dysphagia assessment to define the safest feeding route for the patient.

Nucleobindin 2/nesfatin-1 expression and colocalisation with neuropeptide Y and cocaine- and amphetamine-regulated transcript in the human brainstem

Feeding is a complex behaviour entailing elaborate interactions between forebrain, hypothalamic and brainstem neuronal circuits via multiple orexigenic and anorexigenic neuropeptides. Nucleobindin-2 (NUCB2)/nesfatin-1 is a negative regulator of food intake and body weight with a widespread distribution in rodent brainstem nuclei. However, its localisation pattern in the human brainstem is unknown. The present study aimed to explore NUCB2/nesfatin-1 immunoexpression in human brainstem nuclei and its possible correlation with body weight. Sections of human brainstem from 20 autopsy cases (13 males, seven females; eight normal weight, six overweight, six obese) were examined using immunohistochemistry and double immunofluorescence labelling. Strong immunoreactivity for NUCB2/nesfatin-1 was displayed in various brainstem areas, including the locus coeruleus, medial and lateral parabrachial nuclei, pontine nuclei, raphe nuclei, nucleus of the solitary tract, dorsal motor nucleus of vagus (10N), area postrema, hypoglossal nucleus, reticular formation, inferior olive, cuneate nucleus, and spinal trigeminal nucleus. NUCB2/nesfatin-1 was shown to extensively colocalise with neuropeptide Y and cocaine- and amphetamine-regulated transcript in the locus coeruleus, dorsal raphe nucleus and solitary tract. Interestingly, in the examined cases, NUCB2/nesfatin-1 protein expression was lower in obese than normal weight subjects in the solitary tract (P = 0.020). The findings of the present study provide neuroanatomical support for a role for NUCB2/nesfatin-1 in feeding behaviour and energy balance. The widespread distribution of NUCB2/nesfatin-1 in the human brainstem nuclei may be indicative of its pleiotropic effects on autonomic, neuroendocrine and behavioural processes. In the solitary tract, a key integrator of energy status, altered neurochemistry may contribute to obesity. Further research is necessary to decipher human brainstem energy homeostasis circuitry, which, despite its importance, remains inadequately characterised.

Dysphagia prognosis prediction via corticobulbar tract assessment in lateral medullary infarction: a diffusion tensor tractography study

We investigated the capacity for dysphagia prognosis prediction using diffusion tensor tractography (DTT) to assess the state of the corticobulbar tract (CBT) during the initial period following lateral medullary infarction (LMI). Twenty patients with LMI and 20 control subjects were recruited for this study. The patients were classified into two subgroups: subgroup A (16 patients with nasogastric tube required for six months or less after LMI onset) and subgroup B (4 patients with nasogastric tube required for more than six months after onset). DTT was used to reconstruct the CBTs of each patient and control subject, and the fractional anisotropy (FA) and tract volume (TV) measurements were obtained. In the affected hemisphere, the FA value of the CBT was significantly lower in subgroup B than in subgroup A and the control group (p < 0.05), with no significant difference between subgroup A and the control group. In the affected and unaffected hemispheres, the TV values of CBT in subgroups A and B were lower than those of the control group (p < 0.05), with no significant difference between subgroups A and B. In addition, among the four patients of subgroup B, reconstruction of the CBT was not possible in three patients, and the remaining patients exhibited on old lesion in the corona radiate involving descending pathway of the CBT in the affected hemisphere. We found that the injury severity of the CBT in the affected hemisphere appeared to be related to a poor dysphagia prognosis following LMI. Our results suggest that evaluation of the CBT state during the early post-LMI could be useful for dysphagia prognosis prediction.

Dysphagia in Lateral Medullary Syndrome: A Narrative Review

Dysphagia is a common clinical feature of lateral medullary syndrome (LMS) and is clinically relevant because it is related to aspiration pneumonia, malnutrition, increased mortality, and prolonged hospital stay. Herein, the pathophysiology, prognosis, and treatment of dysphagia in LMS are reviewed. The pathophysiology, prognosis, and treatment of dysphagia in LMS are closely interconnected. Although the pathophysiology of dysphagia in LMS has not been fully elucidated, previous studies have suggested that the medullary central pattern generators coordinate the pharyngeal phases of swallowing. Investigation of the extensive neural connections of the medulla oblongata is important in understanding the pathophysiologic mechanism of dysphagia in LMS. Previous studies have reported that most patients with dysphagia in LMS have a relatively good prognosis. However, some patients require tube feeding for several months, even years, due to severe dysphagia, and little has been reported about conditions associated with a poor prognosis of dysphagia in LMS. Concerning specific therapeutic modalities for dysphagia in LMS, in addition to general modalities used for dysphagia treatment in stroke patients, non-invasive modalities, including repetitive transcranial magnetic stimulation and transcranial direct current stimulation, as well as invasive modalities, such as botulinum toxin injection, balloon catheter dilatation, and myotomy for relaxation of the cricopharyngeal muscle, have been applied. For the appropriate application of therapeutic modalities, clinicians should be aware of the recovery mechanisms and prognosis of dysphagia in LMS. Further studies on this topic, as well as studies involving large numbers of subjects on specific therapeutic modalities, should be encouraged.

Transcranial direct current stimulation improves the swallowing function in patients with cricopharyngeal muscle dysfunction following a brainstem stroke

OBJECTIVE

This study investigated the effects of transcranial direct current stimulation (tDCS) combined with conventional swallowing training on the swallowing function in brainstem stroke patients with cricopharyngeal muscle dysfunction (CPD).

METHODS

Twenty-eight brainstem stroke patients with CPD were assigned randomly to an anodal tDCS group or a sham tDCS group. The patients received anodal tDCS or sham tDCS over the bilateral oesophageal cortical area combined with simultaneous catheter balloon dilatation and conventional swallowing therapy for 20 days. Swallowing function was assessed using the functional oral intake scale (FOIS) and the functional dysphagia scale (FDS) and by measuring the pharyngoesophageal Segment Opening (PESO) before and immediately after the intervention.

RESULTS

Both groups showed a significant improvement in the FDS, FOIS and PESO scores immediately after the intervention (all p < .005). However, compared with the sham stimulation group, the anodal tDCS group showed greater improvements in the FDS, FOIS and PESO scores immediately after the intervention (all p < .005).

CONCLUSION

The bihemispheric anodal tDCS combined with simultaneous catheter balloon dilatation and conventional swallowing therapy effectively improves the swallowing function in patients with CPD caused by a brainstem stroke. tDCS may be an effective adjuvant therapy in CPD rehabilitation.

The BDNF polymorphism Val66Met may be predictive of swallowing improvement post pharyngeal electrical stimulation in dysphagic stroke patients

BACKGROUND

The aim of this study was to explore the effect of brain-derived neurotrophic factor (BDNF) polymorphism rs6265 (Val66Met) in both "natural" and treatment induced recovery of swallowing after dysphagic stroke.

METHODS

Sixteen dysphagic stroke patients that completed a single-blind randomized sham controlled trial of pharyngeal electrical stimulation (PES) within 6 weeks of their stroke (N=38), were genotyped for the BDNF SNP Val66Met (rs6265) from saliva samples. These patients received active or sham PES according to randomized allocation. PES was delivered at a set frequency (5 Hz), intensity (75% of maximal tolerated), and duration (10 minutes) once a day for three consecutive days. Clinical measurements were taken from patients at baseline, 2 weeks and 3 months post entering the study. Changes in swallowing ability based on the dysphagia severity rating scale (DSRS) were compared between active and sham groups and associated with BDNF SNP status.

KEY RESULTS

In the active stimulation group, patients with the Met BDNF allele demonstrated significantly greater improvements in DSRS at 3 months compared to patients homozygous for the Val allele (P=.009). By comparison, there were no significant associations at the 2 week stage in either the active or sham group, or at 3 month in the sham group. Functional scores including the Barthel Index and modified Rankin scale were also unaffected by BDNF status.

CONCLUSIONS & INFERENCES

Our findings suggest an association between BDNF and stimulation induced swallowing recovery. Further work will be required to validate these observations and demonstrate clinical utility in patients.

Ineffective esophageal motility and the vagus: current challenges and future prospects

Ineffective esophageal motility (IEM) is characterized by low to very low amplitude propulsive contractions in the distal esophagus, hence primarily affecting the smooth muscle part of the esophagus. IEM is often found in patients with dysphagia or heartburn and is commonly associated with gastroesophageal reflux disease. IEM is assumed to be associated with ineffective bolus transport; however, this can be verified using impedance measurements or evaluation of a barium coated marshmallow swallow. Furthermore, water swallows may not assess accurately the motor capabilities of the esophagus, since contraction amplitude is strongly determined by the size and consistency of the bolus. The “peristaltic reserve” of the esophagus can be evaluated by multiple rapid swallows that, after a period of diglutative inhibition, normally give a powerful peristaltic contraction suggestive of the integrity of neural orchestration and smooth muscle action. The amplitude of contraction is determined by a balance between intrinsic excitatory cholinergic, inhibitory nitrergic, as well as postinhibition rebound excitatory output to the musculature. This is strongly influenced by vagal efferent motor neurons and this in turn is influenced by vagal afferent neurons that send bolus information to the solitary nucleus where programmed activation of the vagal motor neurons to the smooth muscle esophagus is initiated. Solitary nucleus activity is influenced by sensory activity from a large number of organs and various areas of the brain, including the hypothalamus and the cerebral cortex. This allows interaction between swallowing activities and respiratory and cardiac activities and allows the influence of acute and chronic emotional states on swallowing behavior. Interstitial cells of Cajal are part of the sensory units of vagal afferents, the intramuscular arrays, and they provide pacemaker activity to the musculature that can generate peristalsis in the absence of innervation. This indicates that a low-amplitude esophageal contraction, observed as IEM, can be caused by a multitude of factors, and therefore many pathways can be potentially explored to restore normal esophageal peristalsis.

Persistent post-stroke dysphagia treated with cricopharyngeal myotomy

Post-stroke dysphagia is a common problem after stroke. About 8-13% patients have persistent dysphagia and are unable to return to pre-stroke diet even after 6 months of stroke. Use of percutaneous endoscopic gastrostomy (PEG) may be required in these patients, which may be psychologically unacceptable and impair the quality of life. In those with cricopharyngeal dysfunction leading on to refractory post-stroke dysphagia, cricopharyngeal myotomy and injection of botulinum toxin are the treatment options. We present a case of vertebrobasilar stroke who had persistent dysphagia due to cricopharyngeal dysfunction with good recovery of swallowing function following cricopharyngeal myotomy 1.5 years after the stroke.

Disfagia orofaríngea na Síndrome de Wallenberg - série de casos

RESUMO: Objetivo: caracterizar o quadro de comprometimento da função da deglutição em pacientes com Síndrome de Wallenberg. Métodos: série de casos de sete pacientes, com diagnóstico dessa síndrome, encaminhados para avaliação fonoaudiológica. Para avaliação do grau de disfagia utilizou-se a escala Gugging Swallowing Screen e para avaliar o nível de ingestão oral utilizou-se a Functional Oral Intake Scale. Resultados: a média de idade foi de 60,57 anos; todos os sujeitos apresentaram alteração na função da deglutição de grau grave (71,42%) a moderado (28,58%); 85,71% necessitaram de Via Alternativa de Alimentação, sendo que, 71,43% eram alimentados exclusivamente por sonda nasoentérica; todos necessitaram de acompanhamento fonoaudiológico. Conclusão: este estudo concluiu que a disfagia orofaríngea na Síndrome de Wallenberg apresenta-se como um distúrbio de grau grave a moderado, sendo necessária a utilização de Via Alternativa de Alimentação na maioria dos casos.

Expanding Instrumental Options for Dysphagia Diagnosis and Research: Ultrasound and Manometry

Diagnostic assessment of swallowing in routine clinical practice relies heavily on the long-standing techniques of videofluoroscopic swallowing study (VFSS) and videoendoscopic evaluation of swallowing (VEES). These complementary and sophisticated techniques provide a real-time visualization of biomechanical movements of the structures involved in swallowing and consequent effects on bolus flow. Despite the sophistication of this instrumentation, interpretation relies heavily on subjective clinical judgement and temporal resolution is limited, limitations that may influence patient management. Adjunctive diagnostic assessments may be utilized to compensate for the limitations posed by VFSS and VEES. Ultrasound and pharyngeal manometry do not represent the latest in technological advances, with both emerging in swallowing research over 20 years ago. However, both have resisted integration into routine clinical practice, despite the fact that they offer quantitative metrics of swallowing that are not available using standard techniques. The aim of this review is to present recent research on these two less frequently used modalities in clinical swallowing assessment, discuss potential applications in clinical practice and review supportive data on test-retest reliability, rater reliability and validity. The paper will conclude with a case report that exemplifies the unique contribution of these modalities in executing and revising therapeutic approaches for a patient with neurogenic dysphagia.

Dysphagia and aspiration as the only manifestations of a stroke

A 56-year-old patient was admitted to our hospital, presenting with dysphagia as the only symptom. He was very concerned about this difficulty in swallowing. Diseases of the upper digestive tract were suspected, but further investigations revealed a neurological disorder. He had suffered a brain stem stroke and, as a consequence, developed an aspiration pneumonia. What seemed a digestive disorder was indeed a brain stem stroke, therefore we had to deal with the diverse impacts of this condition.

Oropharyngeal Dysphagia: neurogenic etiology and manifestation

To determine the type, severity and manifestation of dysphagia in patients with neurogenic etiology. Clinical documentation was done on the different etiologies, its manifestation, assessment findings and management strategies taken for patients with neurogenic oropharyngeal dysphagia who were referred for assessment and management of dysphagia over a period of three months in a tertiary care teaching hospital. Flexible endoscopic examination was done in all the patients. The severity of dysphagia in these patients were graded based on Gugging Swallowing Screen (GUSS). A total of 53 patients with neurogenic oropharyngeal dysphagia were evaluated by an otolaryngologist and a speech language pathologist over a period of three months. The grading of severity based on GUSS for these patients were done. There were 30 patients with recurrent laryngeal nerve injury due to various etiologies, one patient with Neurofibroma-vestibular schwanoma who underwent surgical excision, 16 patients with stroke, two patients with traumatic brain injury, two patients with Parkinsonism and two patients with myasthenia gravis. The manifestation of dysphagia was mainly in the form of prolonged masticatory time, oral transit time, and increased number of swallows required for each bolus, cricopharyngeal spasms and aspiration. Among the dysphagia patients with neurogenic etiology, dysphagia is manifested with a gradual onset and is found to have a progressive course in degenerative disorders. Morbidity and mortality may be reduced with early identification and management of neurogenic dysphagia.

Post-stroke dysphagia: progress at last

Oropharyngeal Dysphagia (OD) is both underestimated and underdiagnosed as a cause of malnutrition and respiratory complications following stroke. OD occurs in more than 50% of stroke patients. Aspiration pneumonia (AP) occurs in up to 20% of acute stroke patients and is a major cause of mortality after discharge. Systematic screening for OD should be performed on every patient with stroke before starting oral feeding, followed, if appropriate by clinical and instrumental (videofluroscopy and/or fiberoptic endoscopy) assessment. Bolus modification with adaptation of texture and viscosity of solids and fluids and postural adjustments should be part of the minimal treatment protocol, but they do not change the impaired swallow physiology nor promote recovery of damaged neural swallow networks in stroke patients. To this purpose, two new neurostimulation approaches are being developed to stimulate cortical neuroplasticity to recover swallowing function: (i) those aimed at stimulating the peripheral oropharyngeal sensory system by chemical, physical or electrical stimulus; and (ii) those aimed at directly stimulating the pharyngeal motor cortex, such as repetitive transcranial magnetic stimulation (rTMS). The study of Park et al. in this issue of Neurogastroenterology and Motility evaluated the effect of rTMS in dysphagic stroke patients and showed a marked improvement in swallow physiology. Other studies also using rTMS showed plastic changes in pharyngeal motor cortical areas relevant to swallowing function. If further randomized controlled trials confirm these initial results, the neurorehabilitation strategies will be introduced to clinical practice sooner rather than later, improving the recovery of dysphagic stroke patients. Progress at last.

Functional connectivity of the cortical swallowing network in humans

INTRODUCTION

Coherent fluctuations of blood oxygenation level dependent (BOLD) signal have been referred to as "functional connectivity" (FC). Our aim was to systematically characterize FC of underlying neural network involved in swallowing, and to evaluate its reproducibility and modulation during rest or task performance.

METHODS

Activated seed regions within known areas of the cortical swallowing network (CSN) were independently identified in 16 healthy volunteers. Subjects swallowed using a paradigm driven protocol, and the data analyzed using an event-related technique. Then, in the same 16 volunteers, resting and active state data were obtained for 540 s in three conditions: 1) swallowing task; 2) control visual task; and 3) resting state; all scans were performed twice. Data was preprocessed according to standard FC pipeline. We determined the correlation coefficient values of member regions of the CSN across the three aforementioned conditions and compared between two sessions using linear regression. Average FC matrices across conditions were then compared.

RESULTS

Swallow activated twenty-two positive BOLD and eighteen negative BOLD regions distributed bilaterally within cingulate, insula, sensorimotor cortex, prefrontal and parietal cortices. We found that: 1) Positive BOLD regions were highly connected to each other during all test conditions while negative BOLD regions were tightly connected among themselves; 2) Positive and negative BOLD regions were anti-correlated at rest and during task performance; 3) Across all three test conditions, FC among the regions was reproducible (r>0.96, p<10(-5)); and 4) The FC of sensorimotor region to other regions of the CSN increased during swallowing scan.

CONCLUSIONS

1) Swallow activated cortical substrates maintain a consistent pattern of functional connectivity; 2) FC of sensorimotor region is significantly higher during swallow scan than that observed during a non-swallow visual task or at rest.

Dysphagia due to Retropharyngeal Abscess that Incidentally Detected in Subarachnoid Hemorrhage Patient

Cerebral hemorrhage is one of the most common causes of dysphagia. In many cases, dysphagia gets better once the acute phase has passed. Structural lesions such as thyromegaly, cervical hyperostosis, congenital web, Zenker's diverticulum, neoplasm, radiation fibrosis, and retropharyngeal abscess must be considered as other causes of dysphagia as well. Retropharyngeal abscess seldom occur in adults and if it does so, a search for a prior dental procedure, trauma, head and neck infection is needed. The symptoms may include neck pain, dysphagia, sore throat, and in rare cases, dyspnea accompanied by stridor. We present a case and discuss a patient who had dysphagia and neck pain after a cerebral hemorrhage. Testing revealed a retropharyngeal abscess. The symptoms were successfully treated after the administration of antibiotics.

Prediction of dysphagia severity: an investigation of the dysphagia patterns in patients with lateral medullary infarction

OBJECTIVE

In order to identify the factors that influence the swallowing function in patients who develop Wallenberg syndrome (WS) following lateral medullary infarction (LMI), we examined various patient characteristics, including the passage pattern abnormality (PPA) of a bolus through the upper esophageal sphincter (UES).

METHODS

Fifty-four pure LMI patients with dysphagia participated in this study. PPA, defined as the failure of bolus passage through the UES corresponding to the intact side of the medulla, was identified during videofluorographic swallowing evaluations of each patient. On brain magnetic resonance imaging, the subjects' lesions were classified vertically into three levels and horizontally into seven levels in relation to the involvement of the ambiguous and/or solitary nuclei. Logistic regression analyses were performed for age, sex, PPA and the vertical and horizontal sites of the lesions.

RESULTS

In terms of severity, 15 subjects were categorized as having mild dysphagia, 26 subjects were categorized as having moderate dysphagia and 13 were categorized as having severe dysphagia. Subjects with cephalic lesions, greater vertical spread of the lesion and PPA were more likely to have severe dysphagia. PPA and a greater vertical spread of the lesion were related to the severity of the functional outcome (p<0.01). The horizontal extent of the lesion was not strongly related to the prognosis.

CONCLUSION

The presence of PPA in LMI patients is suggestive of abnormalities in the swallowing pattern and, in turn, damage to the medullary central pattern generator. The presence of PPA and a greater vertical spread of the lesion can be useful predictors of severe dysphagia.

Swallowing disorders after ischemic stroke

OBJECTIVE

To investigate occurrences of swallowing disorders after ischemic stroke.

METHOD

This was a retrospective study on 596 medical files. The inclusion criterion was that the patients needed to have been hospitalized with a diagnosis of ischemic stroke; the exclusion criteria were the presence of associated cardiac problems and hospital stay already more than 14 days.

RESULTS

50.5% were men and 49.5% women; mean age 65.3 years (SD= ± 11.7) (p ≤ 0.001). Among the risk factors, 79.4% had hypertension, 36.7% had diabetes (p ≤ 0.001) and 42.7% were smokers. 13.3% of the patients died. Swallowing disorders occurred in 19.6%, among whom 91.5% had mild difficulty and 8.5% had severe difficulty. 87.1% had spontaneous recovery after a mean of 2.4 months. A lesion in the brainstem region occurred in 6.8% (p ≤ 0.001).

CONCLUSION

Swallowing disorders occurred in almost 20% of the population and most of the difficulty in swallowing found was mild. The predictors for swallowing disorders were older age, diabetes mellitus and lesions in the brainstem region.

Swallowing disturbance pattern relates to brain lesion location in acute stroke patients

BACKGROUND AND PURPOSE

The relationship of brain lesion location and swallowing disturbance pattern has been poorly studied in acute stroke patients.

METHODS

Sixty patients with first-ever acute ischemic stroke at clearly assessed location and clinical signs of dysphagia were studied. Swallowing-related parameters rated clinically and fiberendoscopically were attention deficit, buccofacial apraxia, orofacial paresis, gag reflex, delay of pharyngeal swallow, pharyngeal contraction, larynx elevation, function of upper esophageal sphincter (UES), and aspiration severity.

RESULTS

Attention deficit was independently predicted only by parietotemporal infarction, buccofacial apraxia by left-sided parietotemporal infarction, orofacial paresis by infarction encompassing upper motor neuron of cranial nerves, and impaired UES opening by lateral medullary infarction. Other swallowing parameters were not related to lesion topology. On posthoc analysis, pneumonia within 21 days after stroke was predicted only by insular lesion.

CONCLUSIONS

Distinct acute brain lesion locations result in characteristic swallowing disturbance patterns. Dysphagic patients with insular stroke appear to have even higher risk of pneumonia suggesting a further associated factor promoting infection in these subjects.

Submental sEMG and hyoid movement during Mendelsohn maneuver, effortful swallow, and expiratory muscle strength training

PURPOSE

This study investigated the concurrent biomechanical and electromyographic properties of 2 swallow-specific tasks (effortful swallow and Mendelsohn maneuver) and 1 swallow-nonspecific (expiratory muscle strength training [EMST]) swallow therapy task in order to examine the differential effects of each on hyoid motion and associated submental activation in healthy adults, with the overall goal of characterizing task-specific and overload properties of each task.

METHOD

Twenty-five healthy male and female adults (M = 25 years of age) participated in this prospective, experimental study with 1 participant group. Each participant completed all study tasks (including normal swallow, Mendelsohn maneuver swallow, effortful swallow, and EMST task) in random order during concurrent videofluoroscopy and surface electromyography recording.

RESULTS

Results revealed significant differences in the trajectory of hyoid motion as measured by overall displacement and angle of elevation of the hyoid bone. As well, timing of hyoid movement and amplitude differences existed between tasks with regard to the activation of the submental musculature.

CONCLUSIONS

Study results demonstrated differential effects of the 3 experimental tasks on the principles of task specificity and overload. These principles are important in the development of effective rehabilitative programs. Subsequent direction for future research is suggested.

Impaired opening of the upper esophageal sphincter in patients with medullary infarctions

The aim of this study was to report on nine dysphagic patients with medullary infarction and to evaluate swallowing characteristics based on the location of the lesions.We retrospectively reviewed the medical records of these nine patients. The medullary lesions were midlateral (three patients), dorsolateral (one patient), inferodorsolateral (four patients), and paramedian (one patient). The levels of the lesions were upper (four patients), middle (two patients), upper and middle (two patients), and middle and lower medulla (one patient). Dysphagia after medullary infarction was more common in patients with upper or middle medullary level and dorsolateral medullary level lesions. The common findings on videofluoroscopic swallowing studies in patients with lateral medullary infarctions were impaired upper esophageal sphincter opening, aspiration from pyriform sinuses' residue caused by pharyngeal weakness, and multiple swallowing to clear boluses from the pharynx to the esophagus. In patients with medullary infarctions, the lesion levels and loci and their related clinical findings can be useful in predicting dysphagia and aspiration. Because severe dysphagia with serious complication is very common in patients with medullary infarctions, active diagnostic and therapeutic approaches are needed.

Wallenberg's Syndrome: An Unusual Case of Dysphagia

A 56-year-old man presented with sudden-onset oropharyngeal dysphagia and vomiting of central etiology. Neurological evaluation showed uvula deviation to the left, paresis of the mid-right portion of the soft palate, lateralization of gaze to the right side, and dysphonia. Magnetic resonance imaging (MRI) showed an infarction in the left lateral medullary region, therefore the diagnosis of Wallenberg's syndrome was established. The neurological issues along with the dysphagia gradually improved and the patient was discharged.

Lewy body dysphagia

The presence of Lewy bodies (LB) in autonomic structures of the central and peripheral nervous system in Parkinson's disease (PD) is well known and could explain clinical signs of pure autonomic failure (PAF) or dysphagia, frequently associated with the disorder. There are many neuropathological reports in the literature with detailed descriptions of PAF, however, LB dysphagia has thus far only been reported once. In the present study, we describe two cases of isolated dysphagia without extrapyramidal syndrome, diagnosed clinically as progressive supranuclear palsy and amyotrophic lateral sclerosis, where detailed neuropathological examination identified LBs in the dorsal vagal motor nuclei in the medulla. These findings confirm the existence of isolated LB dysphagia and emphasize the importance of detailed neuropathological and immunohistochemical examination in cases of dysphagia.

Surface electromyographic activity of the submental muscles during swallow and expiratory pressure threshold training tasks

The use of expiratory muscle strength trainers improves parameters related to pulmonary function, speech, and cough in both healthy and patient populations. Recently, it has been speculated that expiratory strength training may alter the force generation of muscles used during the swallow process. Specifically, the use of the trainer may result in increased activation of the submental muscle complex. Support for this hypothesis was tested by examining the timing and amplitude of submental muscle activity obtained using surface EMG. These muscles are known to be important for normal swallow function. Twenty participants (10 males, 10 females; mean age = 29 years) were recruited to participate in a one-session study. Participants were asked to perform two swallows (saliva swallow and water swallow) and develop an expiratory pressure set at 25% and 75% of their maximum expiratory pressure (MEP) using an expiratory muscle strength trainer. These tasks allowed comparison of muscle activity during both the swallow and expiratory tasks completed with the trainer. Results indicated that the patterns of activation in the submental muscle group while training on the expiratory device had longer duration of activation with higher amplitude of EMG activity when compared with the swallowing condition. These findings indicate that expiratory muscle strength training (EMST) increases motor unit recruitment of the submental muscle complex. Discussion centers on the potential benefit of EMST as a treatment modality for dysphagia characterized by decreased amplitude of hyoid movement during swallowing.

Pathophysiological changes of the gastrointestinal tract in ischemic stroke

OBJECTIVE

Dysphagia is common after stroke and represents a marker of poor prognosis. After ischemic stroke, dysphagia represents only one part of the clinical spectrum of changes in the gastrointestinal (GI) tract and includes GI hemorrhage, delayed GI emptying, and colorectal dysfunction. State-of-the-art imaging techniques have started to revolutionize to study the cortical and brainstem control of these GI symptoms. It has become increasingly obvious that GI alterations after stroke are complex and its recovery following stroke is even more so.

METHODS

In this review, an electronic database research was performed in MEDLINE, EMBASE, and the COCHRANE database using the terms stroke, dysphagia, GI motility, or cortical reorganization; an extensive manual searching was additionally conducted.

RESULTS

Cerebral ischemia may lead to an interruption of the axis between central nervous system and GI system. This altered interrelation between the central nervous system and the GI system may cause, among other things, mainly dysphagia, GI dysmotility, and GI hemorrhage. The consecutive clinical symptoms can often be directly attributed to specific cerebral ischemic lesions involving the brain stem as well as certain cortical and subcortical structures. However, in some cases the pathophysiological mechanisms leading to GI symptoms are incompletely understood. Recent improvement of imaging techniques, especially in functional imaging, has lead to new insights of the central control of the GI tract, suggesting that its cortical and medullar organization is multifocal, and bilateral with handness-independent hemispheric dominance.

CONCLUSIONS

Following stroke, patients may have swallowing impairment and other changes of the GI tract that could affect nutritional and hydration status and that lead to aspiration pneumonia. Impaired nutritional status is associated with reduced functional improvement, increased complication rates, and prolonged hospital stays.

Substance P and swallowing after stroke

In the field of digestive tract surgery, QOL can be significantly decreased in patients who experience recurrence or metastasis of a cancer, not only by digestive tract disorders that prevent the patient from taking a meal, but also by installation of gastric or ileus tubes. For such patients, surgical procedures aimed to palliate their symptoms are necessary, rather than radical surgeries. We examined 24 cases at our department, for which operations were performed with the aim of palliating their symptoms, during the 4-year period from October 2001 to December 2005. Sixteen (89%) out of 18 symptomatic cases (i.e. patients who could not take a meal, or who had undergone tracheal intubation) exhibited confirmed improvement in their symptoms after the operations. On the other hand, we also experienced one case in which installation of an ileus tube was necessary after the operation (1 case, 5.5%). Five patients (20.9%) died after the operation, before they were discharged from the hospital. For such patients, additional minimally invasive procedures should have been taken into consideration.

Intermittent oro-esophageal tube feeding in acute stroke patients -- a pilot study

OBJECTIVE

Acute stroke patients with dysphagia are usually fed by nasogastric tube. However, this method sometimes causes pneumonia or diarrhea. We investigated the use of a new feeding procedure called intermittent oro-esophageal (IOE) tube feeding in acute stroke patients with severe dysphagia.

MATERIALS AND METHODS

The IOE method was used in 13 acute stroke patients (68 +/- 14 years old; 12 had a brainstem infarction), who were alert, but had severe dysphagia and a weak pharyngeal reflex. IOE tube feeding was carried out as follows. A feeding tube was passed orally into the lower portion of the esophagus, food supplements were administered through the tube at a rate of approximately 50 ml/min, and the tube was removed after finishing the supplement infusion.

RESULTS

We found that the IOE method had the following advantages: (i) IOE feeding took approximately 15 min; (ii) potentially reduced a risk of complications such as pneumonia and diarrhea; and (iii) oral tube insertion stimulated the oral cavity and pharynx, which may improve the swallowing function. However, the IOE feeding method should not be used in patients who: (i) could not understand the IOE procedure; (ii) had an esophageal hiatal hernia or incomplete peristalsis of the esophagus, as such patients are at risk of having the supplement reflux into the oral cavity.

CONCLUSION

The IOE feeding method may be one of the alternatives to continuous nasogastric tube feeding in acute stroke patients with severe dysphagia, who are alert.

Dysphagia after stroke: incidence, diagnosis, and pulmonary complications

OBJECTIVE

To determine the incidence of dysphagia and associated pulmonary compromise in stroke patients through a systematic review of the published literature.

METHODS

Databases were searched (1966 through May 2005) using terms "cerebrovascular disorders," "deglutition disorders," and limited to "humans" for original articles addressing the frequency of dysphagia or pneumonia. Data sources included Medline, Embase, Pascal, relevant Internet addresses, and extensive hand searching of bibliographies of identified articles. Selected articles were reviewed for quality, diagnostic methods, and patient characteristics. Comparisons were made of reported dysphagia and pneumonia frequencies. The relative risks (RRs) of developing pneumonia were calculated in patients with dysphagia and confirmed aspiration.

RESULTS

Of the 277 sources identified, 104 were original, peer-reviewed articles that focused on adult stroke patients with dysphagia. Of these, 24 articles met inclusion criteria and were evaluated. The reported incidence of dysphagia was lowest using cursory screening techniques (37% to 45%), higher using clinical testing (51% to 55%), and highest using instrumental testing (64% to 78%). Dysphagia tends to be lower after hemispheric stroke and remains prominent in the rehabilitation brain stem stroke. There is increased risk for pneumonia in patients with dysphagia (RR, 3.17; 95% CI, 2.07, 4.87) and an even greater risk in patients with aspiration (RR, 11.56; 95% CI, 3.36, 39.77).

CONCLUSIONS

The high incidence for dysphagia and pneumonia is a consistent finding with stroke patients. The pneumonia risk is greatest in stroke patients with aspiration. These findings will be valuable in the design of future dysphagia research.

The upper oesophageal sphincter

The upper oesophageal sphincter (UOS) is a high-pressure zone comprising functional activity of three adjacent muscles together with cartilage and connective tissue. Its primary function is to allow food into the oesophagus and prevent air ingestion. However, it must also allow the reflux of material during belching or vomiting. Cricopharyngeus is the most important muscle with contributions from inferior pharyngeal constrictor and cervical oesophagus. Basal tone within the UOS is contributed to by all three muscles with asymmetry in the axial plane. Relaxation of the UOS occurs during swallowing as well as in sleep while UOS pressure rises with stress, slow oesophageal distension, intra-oesophageal acid infusion and pharyngeal stimulation with air or water. Many physiological characteristics have been attributed to UOS function following videofluoroscopic swallow examinations, manometry and electromyography but a range of normal values remains controversial and their utility uncertain. The result has been that pathological change is inconsistently characterized and management is instigated without a satisfactory evidence base. In this article, we review the anatomy, physiology and pathophysiology of the UOS along with the current opinions on investigation and treatment of UOS dysfunction.